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Publication numberUS4673772 A
Publication typeGrant
Application numberUS 06/784,035
Publication dateJun 16, 1987
Filing dateOct 4, 1985
Priority dateOct 5, 1984
Fee statusPaid
Also published asCN85108637A, CN85108637B, DE3581251D1, EP0177042A2, EP0177042A3, EP0177042B1
Publication number06784035, 784035, US 4673772 A, US 4673772A, US-A-4673772, US4673772 A, US4673772A
InventorsRyohei Satoh, Muneo Oshima, Minoru Tanaka, Suguru Sakaguchi, Akira Murata, Kazuo Hirota
Original AssigneeHitachi, Ltd.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electronic circuit device and method of producing the same
US 4673772 A
Abstract
In connecting an electronic circuit part such as a semiconductor or other part to a substrate for mounting the part with solder, the solder is composed of a high-melting-point solder portion which is subjected to working such as rolling and heat treatment in order to break the cast structure thereof, and a smaller volume of low-melting-point solder portions. The high-melting-point solder portion is connected to both the electronic circuit substrate and the electronic circuit part through the low-point-melting solder portions.
This method enables interconnection between objects to be connected without impairing the high ductility and toughness of the high-melting-point solder which is subjected to working and heat treatment. This soldering method ensures highly reliable manufacture of miniaturized high density circuits, such as LSI.
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Claims(12)
What is claimed is:
1. An electronic circuit device comprising:
a substrate;
an assembly mounted on said substrate; and
solder for connecting said assembly to said substrate;
said solder being composed of low-melting-point solder portions and a high-melting-point solder portion subjected to working and heat treatment; and
said high-melting-point solder portion being connected to both of said substrate and said assembly through said low-melting-point solder portions.
2. An electronic circuit device according to claim 1, wherein said assembly is an electronic circuit part and said substrate is an electronic circuit substrate.
3. An electronic circuit device according to claim 1, wherein said assembly is a semiconductor chip and said substrate is an electronic circuit substrate to which said semiconductor chip is to be mounted.
4. An electronic circuit device according to claim 1, wherein an electronic circuit part is mounted on said electronic circuit substrate and connected to said substrate with first solder;
a cover for covering said electronic circuit part is connected to said electronic circuit substrate with second solder; and
at least one of said first and second solders is composed of a high-melting-point solder portion which is subjected to working and heat treatment, and low-melting-point solder portions.
5. In a method of connecting a substrate and an assembly which is mounted on said substrate and is to be connected thereto with solder, a method of manufacturing an electronic circuit device comprising the steps of:
preparing solder composed of a low-melting-point solder portion and a high-melting-point solder portion subjected to working and heat treatment;
inserting said low-melting-point solder portions between predetermined positions of said high-melting-point solder portion and predetermined positions of objects to be connected; and
connecting said high-melting-point solder portion to said objects to be connected by melting said low-melting-point solder portions.
6. A method of manufacturing an electronic circuit device according to claim 5, wherein said step of inserting said low-melting-point solder portions between the predetermined positions of said high-melting-point solder portion and the predetermined positions of said objects to be connected is carried out by fusion bonding, in advance, said low-melting-point solder portions at said predetermined positions of said high-melting-point solder portion.
7. A method of manufacturing an electronic circuit device according to claim 5, wherein said step of inserting said low-melting-point solder portions between the predetermined positions of said high-melting-point solder portion and the predetermined positions of said objects to be connected is carried out by fusion bonding, in advance, said low-melting-point solder portions at said predetermined positions of said objects to be connected.
8. A method of manufacturing an electronic circuit device according to claim 5, wherein said assembly is an electronic circuit part and said substrate is an electronic circuit substrate; said method including the steps of inserting said low-melting-point solder portions between said high-melting-point solder portion and said electronic circuit part and between said high-melting-point solder portion and said electronic circuit substrate, and connecting said circuit part and said circuit substrate by heating said solder at a temperature which is lower than the melting temperature of said high-melting-point solder and allows said low-melting-point solder portions to be melted.
9. A method of manufacturing an electronic circuit device according to claim 5, wherein said substrate is an electronic circuit substrate and said assembly is a cover for covering an electronic circuit part which is mounted on said electronic circuit substrate and is to be connected thereto; said method including the steps of inserting said low-melting-point solder portions between said high-melting-point solder portion and said cover and between said high-melting-point solder portion and said electronic circuit substrate, and connecting said cover and said circuit substrate by heating said solder at a temperature which is lower than the melting temperature of said high-melting-point solder and allows said low-melting-point solder portions to be melted.
10. A method of manufacturing an electronic circuit device according to claim 5, said method including the steps of:
forming said high-melting-point solder into a sheet and reinforcing one end surface thereof with a reinforcing sheet which melts at a lower temperature than said high-melting-point solder;
cutting a groove into the reinforced solder from said high-melting-point solder through said high-melting-point solder portion to an intermediate point of said plate; and
connecting an object to be connected and said high-melting-point solder portion with low-melting-point solder which is attached to said end surface of said high-melting-point solder portion.
11. A method of manufacturing an electronic circuit device according to claim 5, said method including the steps of:
forming said high-melting-point solder into a sheet and reinforcing one end surface thereof with a reinforcing sheet which melts at a lower temperature than said high-melting-point solder;
cutting a groove into the reinforced solder from said high-melting-point solder through said high-melting-point solder portion to an intermediate point of said plate;
connecting a first object to be connected and said high-melting-point solder portion with low-melting-point solder which is attached to said end surface of said high-melting-point solder portion;
removing said reinforcing sheet; and
connecting a second object to be connected and the high-melting-point solder portion which is left by the removal of said reinforcing plate with low-melting-point solder which is attached to the other end surface of said high-melting-point solder portion.
12. A method of manufacturing an electronic circuit device according to claim 5, wherein, when said substrate is connected to an electronic circuit assembly, said high-melting-point solder is supplied to a predetermined position between said substrate and said electronic circuit assembly by using a mask with holes formed in correspondence with the pattern of conductors of said electronic circuit assembly.
Description
BACKGROUND OF THE INVENTION

This invention relates to an electronic circuit device and a method of producing the same which improves the reliability of the joints between an electronic circuit part such as a semiconductor chip or a part and a circuit substrate, by mechanical or thermo-mechanical treatment solder with high-melting-point solder (or wrought solder), the solder being subjected to a process which will be described later, and heat treatment.

In the field of electronic circuit devices, so called "surface mounting" methods have been adopted in order to protect semiconductors or parts mechanically and chemically and to improve the productivity and reliability of electronic circuit devices. Among these, a method of connecting a semiconductor chip 1 and the peripheral end surface of a substrate 2 which faces the semiconductor 1 by minute solder 3 through electrodes 4 and 5, as shown in FIG. 1, is known as the mounting method with the highest density (cf. U.S. Pat. No. 3,871,014, or Japanese Patent Publication No. 28735/1968). In these methods, the chip 1 and the circuit substrate 2 are connected using the effect of the wetting and diffusion of the completely melted solder 3 with respect to the electrodes 4 and 5. Since it is necessary to melt the solder completely, segregation of the alloy structure, defects, and residual stress disadvantageously often result during the cooling stage of the solder, so that the solder 3 has a cast structure with low elongation. The solder 3 which have these cast structures have low elongation with respect to external force, producing nonuniform deformation, which leads to the serious problem of the solder 3 being fractured by various kinds of stresses produced during use in a comparatively short period of time due to metal fatigue of the solder 3.

Such a problem of soldering interconnection has become more important with the increasing tendency towards miniaturization of electronic parts and increase in mounting density as in the case of LSI.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to solve the above-described problem and to provide an electronic circuit device which enables highly reliable solder connections, together with a method of manufacturing the same.

To achieve this aim, this invention is characterized in that the ductility of solder is greatly improved by subjecting it to rolling and to heat treatment, and in that the wrought solder which is formed into the shape corresponding to the joints is connected with low-melting-point solder joints which are supplied between parts such as a semiconductor chip and a substrate by local welding at such a low temperature as not to melt the wrought solder, thereby utilizing the ductility and toughness of the wrought solder.

In addition, this invention provides a means for realizing solder connections in the present invention which will enable mass production of high density electronic circuit devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a conventional electronic circuit device;

FIG. 2 shows the characteristic curves of tensile strength in wrought solder according to the invention and solder in the prior art, respectively;

FIGS. 3(a) and 3(b) are photos of the structures of the wrought solder according to the invention and a conventional casting solder;

FIG. 4 is a phase diagram of a Pb - Sn alloy according to the invention;

FIG. 5 is a phase diagram of a Pb - In alloy;

FIG. 6 is a phase diagram of a Pb - Sb alloy;

FIG. 7 is a perspective view of an embodiment of an electronic circuit device according to the invention;

FIG. 8 is a sectional view of the embodiment shown in FIG. 7, taken along the line A--A'.

FIGS. 9(a) to 9(d) are explanatory sectional views of the manufacturing steps of the electronic circuit device shown in FIG. 7;

FIG. 10 is a sectional view of a ceramic package, which is another embodiment of the invention;

FIG. 11 is a sectional view of a surface mounting part of a resistor;

FIGS. 12(a) to 12(d) are explanatory perspective views of the steps of supplying wrought solder;

FIG. 13 is a perspective view of still another embodiment of an electronic circuit device according to the invention; and

FIG. 14 is a sectional view of the device shown in FIG. 13, taken along the line A--A'.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Wrought solder is used in the present invention for the connecting joints between a part and a substrate on the basis of the following phenomenon and principle. Many metals have problems such as gas occlusions and defects when they are melted and solidified, and most alloys form heterogeneous cast structures including crystal segregation and gravity segregation in the solidifying stage. Since such metals and alloys having defects and heterogeneous cast structures are generally brittle and hard, when they are used as structural members, the cast structures are broken by rolling or heat treatment into homogeneous structures in order to improve the toughness and the ductility. However, since solder joints of alloys such as Pb - Sn or Au - Sn are based on melting connection, such solder joints inevitably have cast structures by melting and solidifying, and it is almost impossible to break the cast structure by rolling or heat treatment unlike the above-described case. Therefore, there is no alternative but to use the hard and brittle cast structure without any treatment.

FIG. 2 shows the tension properties of wrought solder pieces a', b', and c' and cast solder pieces a, b, and c, using Pb - Sn alloys as materials. The ordinate denotes the stress (Kg/mm2) and the abscissa the elongation ε (%).

As is obvious from the Figure, all the wrought solder pieces of any composition a', b', and c' are soft and exhibit improvement in elongation. These wrought solder pieces a', b' and c' are formed by making test pieces for a tension test of a sheet which has been prepared by cold rolling at a draft of 90% and subjecting the test pieces to heat treatment at room temperature for about one week. FIG. 3 shows the comparison of the structure of the cast solder piece (as shown in FIG. 3(a), and c in FIG. 2) of 95Pb /5 Sn with that of the wrought solder piece (as shown in FIG. 3(b), and c' in FIG. 2). As shown in FIGS. 3(a) and 3(b), in the structure of the wrought solder piece (as shown in FIG. 3(b)) the grains are finer and the segregated Sn phase of high concentration is spheroidized like spheroidal graphite cast iron and the internal strain is less in comparison with the structure of the cast solder piece (as shown in FIG. 3(a)). The expansion of the wrought solder piece c' is three times or four times as great as that of the cast solder piece c, as is shown in FIG. 2, which fact shows the effects of working and heat treatment on improving the properties of the metal.

The inventors have developed an idea from the above-described phenomenon that a joint, which can sufficiently withstand fatigue and the like caused from various stresses, can be obtained by using the above-described wrought solder. In other words, the desired connection is carried out without losing the tenacity and ductility of wrought solder by melting only the end connecting portion of the wrought solder joint with solder of a lower-melting point than the wrought solder, thereby ensuring a connection of high reliability. In addition, these effects can be expected from almost all solders. FIGS. 4, 5, and 6 are phase diagrams of a Pb - Sn alloy, a Pb - In alloy, and a Pb - Sb alloy, respectively, disclosed by M. Hansen in 1958. As is clear from these Figures, all of the alloys show segregation and heterogeneous structures during the cooling and solidifying stage, and improvement in expansion by working and heat treatment can be expected.

Hereinunder an embodiment of the invention will be explained with reference to FIGS. 7 to 9. FIG. 7 is a perspective view of an electronic circuit device having a connecting structure in accordance with the invention, and FIG. 8 is a sectional view of the embodiment taken along the line A--A'. As shown in the FIGS. 7 and 8, wrought solder elements 6 which are worked and shaped are inserted between the semiconductor chip 1 and the substrate 2 through the electrodes 4 and 5. Solder (not shown) of a lower-melting point than the wrought solder is attached to the electrodes 4 and 5, so that the semiconductor chip 1 and the substrate 2 are connected by melting only this attached solder.

A method of manufacturing the embodiment will next be described with reference to FIGS. 9(a) to 9(d). The substrate 2 may be made of various materials and the electrodes 5 are provided on the substrate 2 by a method suitable to the particular substrate material. For example, if the substrate 2 is made of alumina ceramic, the electrodes 5 are formed by printing conductor paste such as Ag - Pd or W and sintering it. When the conductor paste is W, Ni plating is conducted. Eutectic solder joints 7 of a low-melting point such as solder of Pb - Sn or An - Sn are formed on the electrodes 5 by reflow after solder pasting, solder balls, reflow after vacuum deposition, or solder dipping. Thus the circuit substrate 2 is formed. Low-melting-point solder elements 9 are formed on the electrodes 4 of the semiconductor chip 1 in a similar way to the solder 7. High-melting-point wrought solder joints 8 are next formed into a shape corresponding to the electrode 5, for example, circle, square, or triangle, as is shown in FIG. 9(b). The shape of the wrought solder 8 does not necessarily correspond to the shape of the electrode 5. The composition of the wrought solder 8 is, for example, 95 wt % Pb and 5 wt % Sn, or 80 wt % Au and 20 wt % Sn. The wrought solder 8 here is formed by rolling a dissolved and cast material into a sheet at a draft of 90%, and thereafter subjecting it to heat treatment in an inert atmosphere at a temperature of 50 C. for two days. The wrought solder joints 8 are placed on the circuit substrate 2 at the same position as the low-melting point solder 7. The substrate 2 is heated in this state such that only the low-melting point solder 7 is melted in order to fix the wrought solder 8 on the electrodes 5. The tension properties of this solder 8 substantially agree with those of the solder piece c' as shown in FIG. 2. The semiconductor chip 1 is then placed on the wought solder 8 in such a manner that the low-melting point solder elements 9 are at the same positions as the relevant wrought solder 8, and are heated at a temperature slightly higher than the melting point of the low-melting point solder 7, thereby being connected to the upper portions of the wrought solder 8. Thus the electronic circuit device shown in FIG. 9(d) can be obtained. In this embodiment, the wrought solder 8 is columnar 0.15 mm in diameter and 0.3 mm in length. The wrought solder 8 is supplied to the circuit substrate using a stainless steel mask with holes formed thereon in accordance with the pattern of the electrodes 5. The soldering joints obtained in this way essentially consist of the wrought solder, because, since the melting point of the wrought solder is high and its volume is large, the area of the wrought solder 8 which is connected by melting with the low-melting-point solder 7 is so small, from 20 to 30 μm2. When the life of the wrought solder 8 was evaluated in one cycle/hr test at a temperature cycle of -55 to + 150 C., it was five times as long as a conventional cast solder in case of 95 Pb-5 Sn solder and twice as long as a conventional cast solder in case of 80 Au - 20 Sn solder.

The present invention may be applied by a similar method to a surface mounting part of a ceramic-packaged IC, a condenser, a resistor or the like. For example, this invention can be applied to a connection between a ceramic package 18 and the substrate 2 through the electrodes 4 and 5 with solder 6, as is shown in FIG. 10. The ceramic package 18 is composed of a metallic layer 12 of a molybdenum - manganese layer which is placed on the central portion of a recessed portion 10a of a ceramic substrate 10 provided for receiving an element, the molybdenum - manganese layer being subjected to nickel plating and gold plating; a semiconductor element 13 which is placed on the metallic layer 12; an internal lead 14 formed by plating the ceramic substrate 13 except for the recessed portion 10a with a molybdenum - manganese layer; wires 15 used for wire bonding for the purpose of connecting the internal lead 14 with the semiconductor element 13; and a sealing portion 17 for sealing between a the ceramic substrate 10 and a sealing cover 16 provided above the ceramic substrate 10. This invention is also applicable to connection with the solder 6 between the substrate 2 and a condenser or a resistor 19 through the electrodes 4 and 5, as is shown in FIG. 11. As a result of measurement of the life of the wrought solder 6 in this case, carried out in order to determine the resistance to metal fatigue, the solder 6 showed three to five times longer life than that of a conventional cast solder joint.

When several hundreds of electrodes measuring several hundred μm in diameter are necessary, as in connecting IC of LSI, some problems have been experienced in terms of the method of supplying solder which have been worked in accordance with the electrodes and subjected to heat treatment. According to the invention, a wrought solder sheet 20 is first reinforced with lined hardening flux 21 (which hardens at a temperature of not higher than 100 C.) before they are fixed on a glass sheet 22 or the like, as shown in FIG. 12(a), in order to prevent the electrodes from being disconnected by minute working. The hardening flux 21 used here can be easily removed when desired. The reinforcing material may be solder which has a lower-melting-point than that of the solder sheet 21, and which is plated, deposited or clad by rolling. The solder sheet 20 is next cut and divided at a pitch of several hundred μm into a multiplicity of solder pillars 6 with a wire saw or by electric spark machining, as shown in FIG. 12(b), and the hardening flux beneath the solder sheet 20 is cut downward to an intermediate point in its depth, whereto each solder pillar 6 is fixed. Thereafter, as is shown in FIG. 12(c), the end portion of each solder pillar 6 is brought into contact with a low-melting-point solder 23 such as eutectic solder which has been supplied to the opposing end surface of the part or the semiconductor chip 1 by dipping or the like. In this way, only the low-melting-point solder 23 is melted and all the electrodes and the parts are thereby securely connected. After the hardening flux 21 is removed by dissolving it with solvent such as isopropyl alcohol or trichloroethylene, the part or the semiconductor chip 1 is connected with the circuit substrate 2 by low-meltihg point solder (not shown). Thus the part and the circuit substrate 2 are connected without dissolving the multiplicity of fine solder joints one by one. The method of supplying solder described above is efficient in mass productivity because solder can be supplied not only to each part, but also to the entire surface of, for example, Si wafer, with all electrodes worked collectively.

An embodiment of the invention which is applied to sealing in an electronic circuit device will next be explained with reference to FIGS. 13 and 14. As is shown in FIGS. 13 and 14, in order to seal the semiconductor chip 1 or the part such as a condenser, which is connected with the substrate with solder 24, on the circuit substrate 2, wrought solder 26 is inserted between a cover 25 which covers the portion above the semiconductor chip 1 or a part such as a condenser and the peripheral end portions of the circuit substrate 2 through the electrodes 4 and 5. Solder (not shown) having a lower-melting point than the wrought solder 26 is inserted between the electrodes 4 and 5 and the wrought solder 26, and only the low-melting-point solder is melted, whereby the cover 25 and the circuit substrate 2 are connected by local melting. The interior sealed by the cover 25, the wrought solder 26 and the circuit substrate 2 is a vacuum or an inert gas atmosphere which chemically protects the part. High-melting-point solder is used as the solder 24 for connecting the semiconductor chip 1 or the part such as a condenser with the circuit substrate 2, so as not to be melted when sealing the cover 25 and the circuit substrate 2. The method of manufacturing the electronic circuit device in this case is the same as that shown in FIG. 9.

As described above, this invention enables connection and sealing of semiconductors and electronic circuit parts using wrought solder which has softness, good ductility and fatigue property. Accordingly, a highly reliable electronic circuit device can be obtained with a simple construction and easy operation. Thus this invention can greatly improve the field of surface mounting in which higher reliability and higher density will be increasingly required, for example, it can contribute to upgrading of the functions of an electronic circuit device such as a computer.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3871014 *Aug 14, 1969Mar 11, 1975IbmFlip chip module with non-uniform solder wettable areas on the substrate
US3871015 *Aug 14, 1969Mar 11, 1975IbmFlip chip module with non-uniform connector joints
US4604644 *Jan 28, 1985Aug 5, 1986International Business Machines CorporationSolder interconnection structure for joining semiconductor devices to substrates that have improved fatigue life, and process for making
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4875617 *Jul 14, 1988Oct 24, 1989Citowsky Elya LIntegrated circuits
US4894751 *May 20, 1988Jan 16, 1990Siemens AktiengesellschaftPrinted circuit board for electronics
US4912545 *Sep 16, 1987Mar 27, 1990Irvine Sensors CorporationBonding of aligned conductive bumps on adjacent surfaces
US5007163 *Apr 18, 1990Apr 16, 1991International Business Machines CorporationNon-destructure method of performing electrical burn-in testing of semiconductor chips
US5008736 *Nov 20, 1989Apr 16, 1991Motorola, Inc.Thermal protection method for a power device
US5010387 *Nov 21, 1988Apr 23, 1991Honeywell Inc.Solder bonding material
US5056215 *Dec 10, 1990Oct 15, 1991Delco Electronics CorporationMethod of providing standoff pillars
US5060844 *Jul 18, 1990Oct 29, 1991International Business Machines CorporationInterconnection structure and test method
US5066614 *Sep 28, 1990Nov 19, 1991Honeywell Inc.Method of manufacturing a leadframe having conductive elements preformed with solder bumps
US5075965 *Nov 5, 1990Dec 31, 1991International Business MachinesLow temperature controlled collapse chip attach process
US5130779 *Jun 19, 1990Jul 14, 1992International Business Machines CorporationSolder mass having conductive encapsulating arrangement
US5161729 *Jul 11, 1991Nov 10, 1992Honeywell Inc.Package to semiconductor chip active interconnect site method
US5186383 *Oct 2, 1991Feb 16, 1993Motorola, Inc.Low and high melting alloys, cooling, resolidifying
US5220200 *Jul 23, 1991Jun 15, 1993Delco Electronics CorporationProvision of substrate pillars to maintain chip standoff
US5251806 *Apr 16, 1992Oct 12, 1993International Business Machines CorporationMethod of forming dual height solder interconnections
US5269453 *Oct 8, 1992Dec 14, 1993Motorola, Inc.Low temperature method for forming solder bump interconnections to a plated circuit trace
US5276289 *Mar 25, 1991Jan 4, 1994Hitachi, Ltd.Electronic circuit device and method of producing the same
US5324892 *Aug 7, 1992Jun 28, 1994International Business Machines CorporationMethod of fabricating an electronic interconnection
US5422516 *May 8, 1992Jun 6, 1995Hitachi, Ltd.Electronic parts loaded module including thermal stress absorbing projecting electrodes
US5461261 *Dec 19, 1994Oct 24, 1995Sumitomo Electric Industries, Ltd.Semiconductor device with bumps
US5532612 *Jul 19, 1994Jul 2, 1996Liang; Louis H.Methods and apparatus for test and burn-in of integrated circuit devices
US5540377 *Jul 15, 1994Jul 30, 1996Ito; Carl T.Solder ball placement machine
US5542174 *Sep 15, 1994Aug 6, 1996Intel CorporationMethod and apparatus for forming solder balls and solder columns
US5601675 *Dec 6, 1994Feb 11, 1997International Business Machines CorporationReworkable electronic apparatus having a fusible layer for adhesively attached components, and method therefor
US5641990 *Aug 7, 1995Jun 24, 1997Intel CorporationLaminated solder column
US5675183 *Jul 12, 1995Oct 7, 1997Dell Usa LpHybrid multichip module and methods of fabricating same
US5777847 *Mar 6, 1997Jul 7, 1998Nec CorporationMultichip module having a cover wtih support pillar
US5812379 *Aug 13, 1996Sep 22, 1998Intel CorporationSmall diameter ball grid array pad size for improved motherboard routing
US5860818 *Apr 4, 1994Jan 19, 1999Canon Kabushiki KaishaElectrical connecting member
US5956573 *Jan 17, 1997Sep 21, 1999International Business Machines CorporationUse of argon sputtering to modify surface properties by thin film deposition
US5957370 *Jan 10, 1997Sep 28, 1999Integrated Device Technology, Inc.Plating process for fine pitch die in wafer form
US5982038 *May 1, 1997Nov 9, 1999International Business Machines CorporationCast metal seal for semiconductor substrates
US6023841 *May 6, 1998Feb 15, 2000Concorso; James A.Printed circuit board fixing and mounting procedure for power devices
US6025649 *Jul 22, 1997Feb 15, 2000International Business Machines CorporationPb-In-Sn tall C-4 for fatigue enhancement
US6068923 *Apr 9, 1999May 30, 2000International Business Machines CorporationUse of argon sputtering to modify surface properties by thin film deposition
US6119924 *Nov 3, 1999Sep 19, 2000Murata Manufacturing Co., Ltd.Electronic device having electric wires and method of producing same
US6137693 *Jul 31, 1998Oct 24, 2000Agilent Technologies Inc.High-frequency electronic package with arbitrarily-shaped interconnects and integral shielding
US6166334 *Apr 6, 1999Dec 26, 2000Integrated Device Technology, Inc.Plating process for fine pitch die in wafer form
US6196443Jul 16, 1998Mar 6, 2001International Business Machines CorporationPb-In-Sn tall C-4 for fatigue enhancement
US6259159Jan 30, 1997Jul 10, 2001International Business Machines CorporationReflowed solder ball with low melting point metal cap
US6285083 *Mar 21, 2000Sep 4, 2001Shinko Electric Industries Co., Ltd.Comprising a metallic bump (nickel or copper) electrically connecting the electrode of the semiconductor to conductive pad, increasing melting point and fatigue resistance
US6329721May 15, 2000Dec 11, 2001International Business Machines CorporationPb-In-Sn tall C-4 for fatigue enhancement
US6344234 *Jun 7, 1995Feb 5, 2002International Business Machines CorportionMethod for forming reflowed solder ball with low melting point metal cap
US6492197May 23, 2000Dec 10, 2002Unitive Electronics Inc.Trilayer/bilayer solder bumps and fabrication methods therefor
US6511607Jun 19, 1998Jan 28, 2003Canon Kabushiki KaishaMethod of making an electrical connecting member
US6552642 *May 24, 1999Apr 22, 2003Murata Manufacturing Co., Ltd.Electronic device having electric wires and method of producing same
US6681982 *Jun 12, 2002Jan 27, 2004Advanpak Solutions Pte. Ltd.Pillar connections for semiconductor chips and method of manufacture
US7081404Feb 17, 2004Jul 25, 2006Unitive Electronics Inc.Methods of selectively bumping integrated circuit substrates and related structures
US7156284Mar 2, 2004Jan 2, 2007Unitive International LimitedPositioning metal parts to be bonded; heating while controlling temperature below melting point of metal
US7213740Aug 26, 2005May 8, 2007Unitive International LimitedOptical structures including liquid bumps and related methods
US7287685Sep 20, 2004Oct 30, 2007International Business Machines CorporationStructure and method to gain substantial reliability improvements in lead-free BGAs assembled with lead-bearing solders
US7531898Nov 9, 2005May 12, 2009Unitive International LimitedNon-Circular via holes for bumping pads and related structures
US7547623Jun 29, 2005Jun 16, 2009Unitive International LimitedMethods of forming lead free solder bumps
US7579694Jun 2, 2006Aug 25, 2009Unitive International LimitedElectronic devices including offset conductive bumps
US7731077Jun 7, 2007Jun 8, 2010International Business Machines CorporationStructure and method to gain substantial reliability improvements in lead-free BGAs assembled with lead-bearing solders
US7839000May 8, 2009Nov 23, 2010Unitive International LimitedSolder structures including barrier layers with nickel and/or copper
US7875806Feb 16, 2010Jan 25, 2011International Business Machines CorporationStructure and method to gain substantial reliability improvements in lead-free BGAs assembled with lead-bearing solders
US7879715Oct 8, 2007Feb 1, 2011Unitive International LimitedMethods of forming electronic structures including conductive shunt layers and related structures
US8294269Dec 8, 2010Oct 23, 2012Unitive InternationalElectronic structures including conductive layers comprising copper and having a thickness of at least 0.5 micrometers
US8363422 *Aug 13, 2009Jan 29, 2013Taiyo Yuden Co., Ltd.Electronic component module and method for manufacturing the same
US20100038122 *Aug 13, 2009Feb 18, 2010Fujitsu Media Devices LimitedElectronic component module and method for manufacturing the same
US20120266462 *Nov 10, 2010Oct 25, 2012ThalesSealed electronic housing and method for the sealed assembly of such a housing
EP0747954A2 *May 7, 1996Dec 11, 1996International Business Machines CorporationReflowed solder ball with low melting point metal cap
WO1989002653A1 *Sep 8, 1988Mar 23, 1989Irvine Sensors CorpBonding of aligned conductive bumps on adjacent surfaces
WO1991011833A1 *Jan 17, 1991Aug 8, 1991Commtech IntChip interconnect with high density of vias
Legal Events
DateCodeEventDescription
Sep 28, 1998FPAYFee payment
Year of fee payment: 12
Sep 28, 1994FPAYFee payment
Year of fee payment: 8
Oct 4, 1990FPAYFee payment
Year of fee payment: 4
Dec 24, 1986ASAssignment
Owner name: HITACHI, LTD., 6, KANDA SURUGADAI 4-CHOME, CHIYODA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:SATOH, RYOHEI;OSHIMA, MUNEO;TANAKA, MINORU;AND OTHERS;REEL/FRAME:004648/0173
Effective date: 19850905
Owner name: HITACHI, LTD., A CORP OF JAPAN,JAPAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SATOH, RYOHEI;OSHIMA, MUNEO;TANAKA, MINORU;AND OTHERS;REEL/FRAME:004648/0173